Aberdeen delivered a much-improved display as they began their Europa Conference League campaign with a battling defeat away to Eintracht Frankfurt.
Barry Robson's side, still without a league win this term, held their own against the expensively assembled German side, but Robin Koch's glancing header midway through the second half earned the hosts the points.
Omar Marmoush had put Eintracht in front from the spot after Jack MacKenzie fouled Eric Junior Dina Emimbe, but Dante Polvara equalised from a superb team move to the delight of the travelling Aberdeen contingent.
One of their number, however, was arrested after a pyrotechnic was thrown towards the home fans during the first half.
Aberdeen said they were "deeply disappointed by the actions of a small minority of supporters" and would fully co-operate with the authorities.
Get all your Aberdeen news and analysis all in one placeWhen Marmoush swept home from the spot in the 11th minute, it seemed Aberdeen could be in for a long night, but they were undaunted by the early concession, and hit back with a wonderful goal.
Bojan Miovski drove into space, released the marauding Nicky Devlin down the right, and the Aberdeen wing-back found the unmarked Polvara, who made no mistake from close range, lashing the ball into the roof of the net.
From there, Robson's side impressed. There was a stunning save from Kelle Roos to deny Paxton Aaronson, but Aberdeen went in at the break deservedly level.
Eintracht made changes at the interval, but continued to lack fluency in the opening stages of the second half. However, Koch lost Slobodan Rubezic from a Fares Chaibi corner and glanced a header into the far corner to restore the lead.
That enabled the German side to take more of a grip on proceedings, but there were still moments in the game for Aberdeen, and they could have snatched a point right at the death.
The ball found its way through to Ester Sokler at the back post, but the forward could not hit the target, volleying wide with the home defence helpless.
Player of the match - Nicky Devlin
He played out of his skin, covering every blade of grass and putting his body on the line, keeping Mario Gotze quiet before the German was substituted at the break'Courageous' Aberdeen show signs of progress - analysis
Tyrone Smith, BBC Sport Scotland at the Deutsche Bank Park
Robson will have learned a lot about his Aberdeen players, as they showed bucket loads of character and courage.
Written off by virtually everyone going in to this game, they could have gone under when Frankfurt took the early lead - but they didn't, they stood up and were counted to a man, clearly rattling their illustrious hosts.
Yes, Frankfurt prevailed in the end, but given all the talk pre match about the supposed gulf between the sides, Aberdeen can certainly leave Germany with their heads held high.
Robson got his tactics spot on and will be hoping his side can take positives from this game forward as they seek to revive their stuttering domestic campaign over the coming weeks.
'We could have nicked a draw' - reaction
Aberdeen manager Barry Robson: "I think when you wear that Aberdeen jersey, and you're in Europe, you need to try to show that mentality, desire, fight, tactical know-how, and I thought they did all that in abundance.
"That is a terrific team we faced out there, full of top players. They worked extremely hard, stuck to the tactical plan, and in the last 10 minutes, we could have nicked a draw.
"I trust my players. They're a good bunch, and it's frustrating when it's a set-play and a penalty that's cost you. We're disappointed that we didn't come away with anything, but we need to move onto a big game on Sunday."
Eintracht Frankfurt coach Dino Toppmoller: "We knew it would be hard game, we know they fight for every ball, we know that they have also got good players up front.
"We expected they would play with two strikers, we didn't expect them to defend so deep. But, at the end of the day, we won the game, that is a good thing for us."
What's next?
Aberdeen return to domestic action against Ross County at home on Sunday (15:00 BST).
Their next Conference League outing is against HJK Helsinki at Pittodrie on 5 October, with the Finnish champions opening their Group G account with a 3-2 home win against Greek side PAOK.
Line-ups
Frankfurt
Formation 3-4-3
1Trapp4Koch5Smolcic3Pacho26Dina Ebimbe17RodeSubstituted forLarssonat 39'minutes15Skhiri29NkounkouSubstituted forKnauffat 68'minutes30AaronsonBooked at 25minsSubstituted forNgankamat 45'minutes7MarmoushSubstituted forButaat 83'minutes27GötzeSubstituted forChaïbiat 45'minutesSubstitutes
8Chaïbi16Larsson18Ngankam20Hasebe22Chandler23Hauge24Buta33Grahl35Silva Melo36Knauff47Baum48FerriAberdeen
Formation 5-4-1
24Roos2Devlin6GartenmannBooked at 63mins33Rubezic5Jensen3MacKenzie21PolvaraSubstituted forHayesat 71'minutes10ClarksonSubstituted forBarronat 71'minutes4ShinnieSubstituted forDuncanat 71'minutes7McGrathSubstituted forSoklerat 77'minutes9MiovskiSubstituted forHenriques de Barros Lopesat 56'minutesSubstitutes
8Barron11Henriques de Barros Lopes14Guèye15McGarry17Hayes18R Williams19Sokler23Duncan27MacDonald28Milne30Dadia31DoohanReferee:Chrysovalantis Theouli
Live Text
Match ends, Eintracht Frankfurt 2, Aberdeen 1.
Second Half ends, Eintracht Frankfurt 2, Aberdeen 1.
Robin Koch (Eintracht Frankfurt) wins a free kick in the defensive half.
Foul by Ester Sokler (Aberdeen).
Attempt missed. Ester Sokler (Aberdeen) right footed shot from the centre of the box is high and wide to the right following a set piece situation.
Foul by Farès Chaïbi (Eintracht Frankfurt).
Jonny Hayes (Aberdeen) wins a free kick in the attacking half.
Offside, Aberdeen. Stefan Gartenmann tries a through ball, but Duk is caught offside.
Attempt missed. Farès Chaïbi (Eintracht Frankfurt) right footed shot from outside the box is too high. Assisted by Hugo Larsson.
Foul by Willian Pacho (Eintracht Frankfurt).
Ryan Duncan (Aberdeen) wins a free kick on the left wing.
Ansgar Knauff (Eintracht Frankfurt) wins a free kick in the defensive half.
Foul by Slobodan Rubezic (Aberdeen).
Corner, Aberdeen. Conceded by Junior Dina Ebimbe.
Substitution, Eintracht Frankfurt. Aurélio Buta replaces Omar Marmoush.
Attempt saved. Junior Dina Ebimbe (Eintracht Frankfurt) right footed shot from the right side of the box is saved in the top right corner.
Substitution, Aberdeen. Ester Sokler replaces Jamie McGrath.
Attempt saved. Ansgar Knauff (Eintracht Frankfurt) right footed shot from the left side of the box is saved in the centre of the goal. Assisted by Omar Marmoush.
Attempt missed. Richard Jensen (Aberdeen) header from the centre of the box is high and wide to the left. Assisted by Ryan Duncan with a cross following a corner.
Corner, Aberdeen. Conceded by Willian Pacho.
Player of the match
DevlinNicky Devlin
with an average of 8.23
Eintracht Frankfurt
Squad number36Player nameKnauff
Squad number16Player nameLarsson
Squad number7Player nameOmar Marmoush
Squad number29Player nameNkounkou
Squad number24Player nameAurélio Buta
Squad number8Player nameChaïbi
Squad number5Player nameSmolcic
Squad number18Player nameNgankam
Squad number4Player nameKoch
Squad number30Player nameAaronson
Squad number15Player nameSkhiri
Squad number26Player nameDina Ebimbe
Squad number27Player nameGötze
Squad number1Player nameTrapp
Squad number17Player nameRode
Squad number3Player namePacho
Aberdeen
Squad number2Player nameDevlin
Squad number6Player nameGartenmann
Squad number24Player nameRoos
Squad number9Player nameMiovski
Squad number5Player nameJensen
Squad number21Player namePolvara
Squad number7Player nameMcGrath
Squad number17Player nameHayes
Squad number10Player nameClarkson
Squad number4Player nameShinnie
Squad number23Player nameDuncan
Squad number8Player nameBarron
Squad number33Player nameRubezic
Squad number3Player nameMacKenzie
Squad number19Player nameSokler
Squad number11Player nameDuk